The researchers found that smaller forest fragments had more infected ticks, which could translate to more Lyme disease. Forest patches that were smaller than three acres had an average of three times as many ticks than did larger fragments and seven times more infected ticks. As many as 80 percent of the ticks in the smallest patches were infected, the highest rate the scientists have seen. Although larval ticks hatch in an uninfected condition, they promptly seek a blood meal. In small forest patches, that meal will likely come from white-footed mice, said Keesing.

"Our results suggest that efforts to reduce the risk of Lyme disease should be directed toward decreasing fragmentation of deciduous forests of the northeastern United States into small patches, particularly in areas with a high incidence of Lyme disease," said Keesing. "The creation of forest fragments smaller than five acres should especially be avoided."

The scientists results were published in the February 2003 issue of the journal Conservation Biology.

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Contact: Cheryl Dybas
cdybas@nsf.gov
703-292-8070
National Science Foundation
27-Mar-2003